Thanks Clembo.
I wanted to provide a different Welcome page, not a different Login page as you're referring to. Our guests and colleagues (wanting to onboard) login to the same captive portal. After they login, I want to redirect them to different welcome pages. (I can only send them to a single welcome page via the captive portal profile as far as I know.) The guests would get a "thanks for logging in, you may now browse the web" message, and colleagues would receive the onboarding page. I didn't want to expose the onboarding page to anyone connecting to the guest network, which is why we're making colleagues login to the guest captive portal first. Then, they can click a link on the welcome page to onboard. It may be unnecessary, but that's how it is currently setup. It may just be easier to provide a link on the guest captive portal that sends them to the onboarding page.